1. The Field of the Invention
The present invention relates to cellular network amplifiers. More particularly, embodiments of the present invention relate to systems and methods for dynamically controlling a network amplifier to provide an optimal gain level and to minimize amplifier oscillation.
2. The Relevant Technology
In recent years, cellular (“cell” or “mobile”) telephones have dramatically increased in popularity. A growing number of people are relying exclusively on cell phones, and are abandoning their traditional land line telephone services in favor of the convenience of the mobility of cell phones. Others are simply adding cell phones while retaining land line telephone services. In any case, this increase in cell phone reliance has resulted in the need for reliable cellular signal coverage over a wider area.
Use of cell phones in areas having a weak signal often results in dropped calls which can be annoying for the cell phone user and expensive for the wireless service provider. Dropped calls typically result when the signal between the cell phone and the base station is lost. A loss of signal may occur for a number of reasons, including interference due to buildings or mountains, or an increase in distance between the cell phone and the base station, or for other reasons. Therefore, a particular need exists to increase the reliability of cell phones near large buildings and in vehicles driving long distances in remote areas as well as other reasons.
Attempts have been made to increase the reliability of cell phones through use of cell phone signal boosters, also known as cellular network amplifiers. Cellular network amplifiers receive the cellular signal sent from a base station, amplify the signal, and retransmit the signal to one or more cell phones. Similarly, the cellular network amplifier receives the signals from one or more cell phones, amplifies the signals, and retransmits the signals to the base station.
Cellular network amplifiers are typically placed in relatively close proximity to one or more cell phones, and serve the purpose of increasing the level of the signals being transmitted to and from the cell phones so that the cell phones can communicate with base stations that would otherwise be out of range. Some amplifiers are configured to be integrated with the cell phone itself or with a cell phone cradle. Alternatively, other amplifiers are configured to be placed in a separate location from the cell phone itself. For example, a cellular network amplifier may be placed in a user's vehicle, or in or near a building that might otherwise have poor reception.
Conventional cell phone signal boosters apply constant gain levels to the signal passing through the amplifier. A conventional signal booster typically increases signal power of an uplink or downlink signal using a constant gain level regardless of the level of the received signal. However, if the signal booster receives an uplink signal having a high power level from a cellular telephone and amplifies the uplink signal using the constant gain level, the resultant signal may be amplified beyond a preferred level. Consequently, the signals transmitted from the signal booster may cause interference to be introduced in the surrounding cellular network. The high output levels may also overload the amplifier, causing unwanted distortion. Furthermore, regulatory agencies place upper limits on the cellular signal power levels can be transmitted from a device. By applying a constant level of gain to all signals, a cellular signal amplifier may inadvertently violate these regulations.
The tendency for many cell phone signal boosters to produce unwanted high power levels can create significant problems for wireless service providers by overloading and thereby disrupting cellular systems. Since wireless service providers often evaluate and approve cellular network amplifiers before they are used in the providers' systems, the providers are unlikely to approve signal boosters that produce overamplified signals.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced.